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JOIMAL OP AGMCULTURAL RESEARCH 



Vol. XX Washington, D. C, December 15, 1920 No. 6 



CARBON-DIOXID CONTENT OF BARN AIR 



By Mary F. Hendry and Alice Johnson, Carnegie Nutrition Laboratory, Boston, 

 Mass., and New Hampshire Agricultural Experiment Station 



In connection with the construction and establishment of a respiration 

 chamber 1 for large domestic animals in the dairy barn at the Agricul- 

 tural Experiment Station, Durham, N. H., the question as to the carbon- 

 dioxid content of barn air and its probable influence upon respiration 

 experiments, in case such air should inadvertently leak into the chamber, 

 assumed considerable importance. Recent information with regard to 

 the carbon-dioxid content of barn air is extremely scarce, and the earlier 

 work is practically unrecognized. The extensive investigations of 

 Pettenkofer on ventilation, unfortunately published in a number of small 

 and wholly inaccessible journals, have been cited from time to time by 

 various writers, and to him have been ascribed carbon-dioxid percent- 

 ages in stable air of 0.105 and 0.21 per cent. The most extended serious 

 study of the carbon-dioxid content of barn air was that made by Schultze 

 in the experiment station at Gottingen-Weende, the results of which 

 have been reported by Marcker. 2 Employing the Pettenkofer method, 

 Schultze made nearly 200 analyses of stable air in the vicinity of Gottingen 

 and found that the carbon-dioxid content varied enormously, depending 

 upon the number of animals in the stable, the volume of space available, 

 and the degree of ventilation. The values for the carbon-dioxid per- 

 centages in the air of stables at Weende are as high as 0.435 P er cen t m a 

 number of instances, and a maximum of 0.594 P er cen t is recorded. For 

 outdoor air the usual value of not far from 0.03 per cent to 0.034 P er cen t 

 was found. Marcker concludes that the ventilation of a stable should be 

 such that the carbon dioxid in the air is not greater than 0.25 to 0.30 per 

 cent. Angus Smith cites two analyses of the carbon-dioxid content of 

 air in stables showing but 0.0833 and 0.0875 P er cent. 3 



After our analyses of the air in the dairy barn at Durham were made, 

 our attention was called to the report of the Committee on Farm 



1 Benedict, F. G., Collins, W. E., Hendrv, Mary F., and Johnson, Alice, a respiration chamber 

 For large domestic animals. N. H. Agr. Exp. Sta. Tech. Bui. 16, 27 p., 7 fig. 1920. 



2 Marcker, Max. tjeber den kohlensaure-gehalt der stallluft und den luftwechsel in stal- 

 LUNGEN. In Jour. Landw., Jahrg. 17 (F. 2, Bd. 4), p. 224-275. 1869. We have seen this remarkably 

 complete paper cited but once and then erroneously. It deserves careful study. 



3 Smith, R. A. air and rain. p. so. London, 1872. 



Journal of Agriculture Research, Vol. XX, No. 6 



Washington, D. C Dec. 15, 1920 



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